Heat pumps and the like, such as adsorption refrigerators for automobiles, require a large solvent adsorbing amount, a fast adsorption and desorption rate, and high response for applied pressure. In addition, a certain degree of chemical stability is required because they are exposed to high temperatures. As shown in non-patent literatures 1 to 3 listed below, however, among activated carbons and silica gels, which are regarded as common adsorbents, there is no material that can sufficiently meet the adsorption performance (adsorbing amount, and adsorption and desorption rate) that is currently required. In particular, there has been no material that can adsorb water vapor sufficiently on a high humidity side.
A carbon material for humidity control material has been proposed that is obtained by carbonizing petroleum coke at 650° C. to 850° C. and is characterized by having pores in the range of 20 volume % to 30 volume % (see Patent Literature 1 listed below).